Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 30: Superconductivity: Twenty Years High-Tc Cuprates - Recent Progress
TT 30.15: Vortrag
Donnerstag, 30. März 2006, 17:45–18:00, HSZ 02
Symmetry and shape of the gap function in the hole- and electron-doped superconductors: the functional renormalization-group analysis — •Andrey Katanin1,2 and Arno Kampf3 — 1Max-Planck-Institut für Festkörperforschung, D-70569, Stuttgart, Germany — 2Institute of Metal Physics, 620219 Ekaterinburg, Russia — 3Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany
The problem of symmetry of superconducting pairing and the form of the gap function in the hole- and electron-doped superconductors are considered within the temperature-cutoff functional renormalization group approach combined with the Bethe-Salpeter equations. The momentum dependence of the order parameter for antiferromagnetic and superconducting instabilities in these compounds is analyzed. In the superconducting channel we find significant deviations from the conventional d-wave form of the gap functions. For hole-doped case a higher angular momentum component arises besides the standard dx2−y2-wave component, which flattens the angular dependence of the gap. In the electron-doped case the gap function in the antiferromagnetic (particle-hole) channel has its maxima at the hot spots, or at the diagonal of the Brillouin zone in their absence. The wavefunction in the singlet superconducting channel is non-monotonic in the vicinity of the (π ,0) and (0,π ) points in striking similarity with recent experimental data. The instability in the triplet superconducting channel is much weaker than in the singlet one and has f-wave like form of the gap function.